The field comprising enzymatic additives in detergents has been rapidly growing during the last decades. Reference is made to e.g. the article "How Enzymes Got into Detergents", vol. 12, Developments in Industrial Microbiology, a publication of the Society for Industrial Microbiology, American Institute of Biological Sciences, Washington, D.C. 1971, by Claus Dambmann, Poul Holm, Villy Jensen and Mogens Hilmer Nielsen, and to P. N. Christensen, K. Thomsen and S. Branner: "Development of Detergent Enzymes", paper presented on Oct. 9, 1986 at the 2nd World Conference on Detergents held in Montreux, Switzerland.
Proeolytic detergent additive is widely used in Europe, USA and Japan. In several countries, the majority of detergents, both powder and liquid, contain protease.
The use of lipase as a detergent additive is known. For a comprehensive review we refer to H. Andree et al.: "Lipases as Detergent Components", Journal of Applied Biochemistry, 2, 218-229 (1980). Further examples may be found in U.S. Pat. No. 4,011,169 (column 4, line 65 to column 5, line 68), in GB No. 1,293,613 (page 2, lines 6-29) and in the paper by T. Fujii entitled "Washing of Oil Stains with Lipase" (in Japanese) given at the 16. Symposium on Washing, held in Toyko on Sept. 17-18, 1984.
Among the known lipases used as detergent additives, to the best of our knowledge the Fusarium oxysporum lipase has the best lipolytic characteristics, looked upon from a detergent application point of view, vide Ser. No. 623,404 filed June 22, 1984, especially the comparative Example 27.
If the washing process is conducted at high temperature and high alkalinity, the majority of the fat containing dirt will be removed anyway. However, low or medium temperature washing processes (around 60.degree. C. and below) are now generally used, and at these low temperatures the known lipases are able to dissolve only a small part of the fat containing dirt.
Hitherto the efficiency of lipolytic detergent additives usually has been measured by washing of EMPA (Eidgenossische Materialprufungs- und Versuchsanstalt, St. Gallen, Switzerland) swatches Nos. 101 (olive oil/cotton) and 102 (olive oil/wool) by adaptation of the procedure described in British Pat. No. 1,361,386 (especially pages 4 and 7) and U.S. Pat. No. 3,723,250 (especially col. 15-19). In this way lipolytic cleaning efficiency can be expressed as the differential reflectance value .DELTA.R. However, two more direct measures of the lipolytic action have been employed by the inventors hereof. First, the weight of oil remaining on the textile was determined; this shows the combined effect of detergent and lipase. Second, the remaining oil was analyzed for oil (triglyceride) and decomposition products (mono- and diglyceride, and fatty acid), and the number of unhydrolyzed glyceride bonds in the oil was calculated; this shows more directly the effect of lipase. By use of these latter determinations it has been found that even the best known detergent lipase exhibits a lipolytic detergency effect which is open to improvement. The term detergent lipase is intended to refer to lipases having lipolytic action at alkaline pH conditions.
Furthermore, it is common knowledge that lipases, being proteins, are liable to attack by proteases, and as mentioned above, proteases are today contained in many detergents. There is no publication of a detergent lipase having satisfactory stability in the presence of protease. In fact, it has been found that some known detergent lipases have poor stability in detergent solutions in the presence of commonly used detergent proteases.
Thus, a need exists for a lipolytic detergent additive which exhibits a considerably better lipolytic detergent efficiency at economically reasonable lipase activities in the washing solution and which is stable in detergent solutions containing detergent protease.